Referring to FIG. 10 for a prior art valve, the valve comprises a rectangular body 90, an axle hole 91 penetrating the middle of the body 90, a plurality of valve openings 92 and inlets/outlets 93 disposed on a side of the body 90, and each valve opening 92 and inlet/outlet 93 is interconnected to the axle hole 91, and the axle hole 91 includes a piston 94 therein, and the piston 94 includes a piston rod 95, and each piston rod 95 corresponding to each valve opening 92 includes a plurality of flange sections 96 disposed around each piston rod 95, and each flange section 96 includes an O-ring 97 disposed at the external periphery of the flange section 96, so that a fluid such as a high-pressure gas or a high-pressure liquid can flow through each inlet/outlet 93 and each valve opening 92, and the piston 94 can move reciprocally inside the axle hole 91 of the body 90, so as to control the fluid to enter or exit the valve opening 92 and switch the valve positions for its use.
However, the aforementioned prior art valve still has the following shortcomings in its application:
1. The prior art valve has a short life and a high manufacturing cost. Since the piston rod of the prior art valve moves reciprocally in the axle hole of the body for a long time, each O-ring rubs the internal wall of the axle hole, and the O-ring will be worn out easily. After the valve has been used for some time, there will be a gas leakage and the valve will no longer work properly. Therefore, the prior art valve has a short life, wastes lots of maintenance cost and time, and lowers its efficiency.
2. The prior art valve is difficult to manufacture. Since the internal wall of the axle hole of the body of the prior art valve rubs with the O-ring over a long period of time, therefore the interior of the body must have excellent roundness and smoothness. However, the body is usually slender, and the axle hole cannot be manufactured easily, and thus increasing the level of difficulty and cost of the manufacture.